a quick and dirty function to draw stream graphs

stream_graph.R

# data is a non-negative matrix; x is the timeline vector
stream_graph = function(data, x=1:nrow(data)) {
  m = ncol(data); n = nrow(data)
  data[is.na(data)] = 0
  data = t(apply(cbind(0, as.matrix(data)), 1, cumsum))
  data = sweep(data, 1, rowMeans(data))
  plot(range(x), range(data, na.rm = TRUE), type = 'n', ann = FALSE)
  for (j in 1:m) {
    y = c(data[, j], rev(data[, j + 1]))
    polygon(xspline(c(x, rev(x)), y, shape = -1, draw = FALSE), col = j, border = NA)
  }
}

# test
palette(hsv(seq(0, 1, length = 10), .5, .7))
stream_graph(matrix(runif(1000), 100))